Description
Naked mole-rats (Heterocephalus glaber) exhibit a rich vocal repertoire through which they transmit social signals to conspecifics. They are able to distinguish between individuals from their own or another colony based on these auditory signals. The auditory cortex has been shown to encode for conspecific vocalizations and encode vocalization types in rodents. In addition, in primates, evidence of identity encoding has been found, but it is unclear if this area also encodes individual or social group identity in non-primates. The naked mole-rat’s unique social structure and vocal behaviors make them particularly suitable to determine how social auditory signals are processed in the brain. Therefore, we aimed to record a large population of auditory cortical cells simultaneously using two-photon imaging to determine how social auditory signals are encoded in the naked mole-rat auditory cortex.
We first performed an intracranial injection of a calcium indicator (GCaMP6s) and implanted a cranial window and headplate. This allowed us to performed awake, head-fixed two-photon imaging of the auditory cortex. The animals were exposed to a variety of stimuli, first a battery of pure tones spanning their hearing range, and next a set of conspecific vocalizations both from their own and a different colony. Soft chirps are the most commonly used naked mole-rat vocalizations are have been shown to transmit colony identity. We presented soft chirp vocalizations from 10 different individuals (5 own colony, 5 different colony), as well as various other types of vocalizations with different behavioral contexts, such as whistles, downsweeps and grunts. To analyse this data, we compared the response of the excitatory auditory cortical neurons at a single-cell level to these stimuli and calculated individual preference scores for each cell. This data provides the first insights into how the naked mole-rat auditory cortex responds to socially relevant stimuli.
